I noticed that some 6SN7 tubes are quite valuable, and others won't get a bid. The Tung-Sols seem to command a premium price. Why is this? There must be millions of 6SN7's around as every TV in the 50's had 4 or 5 of them, so it must not be an availibility problem. I've thrown away a bunch of them that came in tube lots I purchased at sales. Maybe that was a mistake.

Hello
I had a few trivial questions about tube preamps. I understand that the forum is dedicated to stompboxes, but I am sure that competent people will help me.
I looked at the scheme of the preamp EVH 5150 III, which is a modernized version of the Peavey 5150/6505.
I have a few questions
1) In most preamplifier circuits, there is a voltage divider in front of the triode; however, before the V5-A, the r66 + r67 design resembles the input circuit of vintage amplifiers, what is called such a...

Hey all,

so here's some tube theory. I'm learning about triodes at the moment, in lieu to building an awesome boosterdrive. Anyway, i've read a few articles about using triodes instead of MOSFETS, but at 9V, i can't seem to get any levels of gain/clipping/overdrive/whatever close to the likes of a J201 or a 2N2222 etc etc. So first question is, can this even be done with 1 triode at 9V???

Second question is, can you use a triode as other types of transistor? whatabout a normal NPN like a...

:scratch:

Hi guys, I've been here for a while, reading, and reading, and reading, and giving opinion some times, since I don't hink I can give the right answer some times.

Well, I am a bass player, and Iove the old sound of the bassman amps (blackface), so I wanna built a 2 channel blackface preamp. This is the schematic I choose:

bass135.jpg

Here are my first concerns:

1.- Is there any problem if I just want to use inputs 1 & 3? I want two channel 'cause I think that a 2nd channel with cranked...